1. Field of the Invention
The present invention relates to shielding structure of an input output terminal portion of a thin type monitor device.
2. Description of Related Art
A connecting terminal to connect with an external device such as a DVD recorder, a game machine, and the like is provided with a thin type monitor device. The connecting terminal includes an input terminal to which a signal from the external device is input, and an output terminal from which a signal is output to the external device. Further, there is a case where a tuner terminal to receive a broadcast signal of television broadcast is also provided with the thin type monitor device.
In a conventional thin type monitor device, the signal which is dealt with between the thin type monitor device and the external device is an analog signal and low frequency signal is mainly used for it. Recently, because performance of the thin type monitor device and the external device become improved, a high frequency digital signal is going to be used between the thin type monitor device and the external device. Further, for the broadcast signal of digital terrestrial broadcasting and satellite broadcasting, digital signal is used. Because the high frequency digital signal is used, it is possible to deal with video signal or audio signal in high quality between the devices without deterioration.
On the other hand, with realization of high performance in the video devices, much noise referred to as electromagnetic interference (hereinafter referred to as “EMI”) has come to output from electronic parts which are mounted on circuit board. This EMI is high frequency noise. The above described high frequency video signal and audio signal are apt to be affected by the EMI. And processed circuit boards which are arranged near the input terminal and/or the output terminal accordingly are covered by a metal box (hereinafter referred to as “shielding box”), the shielding box being grounded, and the influence of the EMI is consequently restrained (see, JP-A-H10-233591, JP-A-2000-068665, and the like).
However, by the conventional shielding box there is a case where not all the outer surfaces of the circuit boards in which influence of the EMI is desired to restrain, can be shielded. In such case, effect of the shielding box for restraining the influence of EMI becomes lower. Further, because the shielding box is grounded by screw fixing or a conducting tape, labor for fixing or a peculiar member is required. As a result, cost for the device becomes high just as much.